A dispute between coworkers exploded into gunfire outside the Empire State Building this morning, leaving at least two dead including the gunman and an innocent bystander — and a total of 10 people shot, sources said.

Responding cops killed the gunman shortly after 9 a.m. at the jam-packed intersection of 34th Street and Fifth Avenue.

It’s unclear what sparked the deadly argument, which happened in the heart of the morning rush on a street loaded with commuters and tourists.

The shot bystanders include a female who died from her wounds, the sources said.

A disgruntled worker stalked a colleague down a Midtown street, shot him dead and then turned his weapon on random pedestrians outside the Empire State Building — killing at least one innocent bystander and shooting up to seven others before he was cut down by a cop on foot patrol, sources told The Post.

The 9 a.m. mayhem sent commuters and tourists in a panicked scramble from the jam-packed intersection of 34th Street and Fifth Avenue.

“This is the last thing you are expecting to see walking to work – someone shot dead in broad daylight in Midtown,” said Sid Dinsay, 38, who works in a PR firm on Fifth Avenue.

“I am shocked – something like this is enough to rattle your nerves. My nerves are rattled right now.”

The gunman followed his victim down 33rd Street before opening fire outside Legend’s Bar. the sources said.

With his target dead, he then headed over to the Empire State Building and did the unthinkable — unleashing a fusillade of shots in the heart of the morning rush on a street loaded with pedestrians.

An NYPD cop on foot patrol — part of the Critical Response Vehicle unit — killed the gunman with one shot.

The shot bystanders include a female who died from her wounds, the sources said. Others were shot in the buttocks and legs.

The victims were taken to St. Luke’s Hospital and Bellevue Hospital.

Dinsay said he heard noise on 33rd street and saw construction workers running on scaffolding on the Empire State Building, looking down onto the street. He thought a piece of equipment had fallen.

“I saw a guy lying there covered in blood,” he said. “He was in his late 30s. People around him were crying, a police scooter was whizzing by. It was chaos.”

The FBI is assisting in the investigation, which has caused a traffic nightmare in Midtown that has effectively shut down all of the streets around the scene.

Eeerily, just minutes before the mayhem, Mayor Bloomberg was warning about the dangers of “too many guns on the streets” on his weekly radio show.

“The argument guns don’t kill people, people kill people is one of the most disingenuous things you can say,” he said shortrly before 9 a.m. while discussing tougher guns laws being proposed in Albany.

“It does take a person to pull the trigger, but if they didn’t have the gun… We are the only developed country in the world with this problem.”

UPDATE 3: Another update from the NY Post, noting the shooter was fired yesterday and came back to kill boss:

The carnage started when the gunman followed his boss, who had fired him yesterday, down 33rd Street before opening fire outside Legend’s Bar, the sources said.

With his target dead, he then headed over to the Empire State Building and did the unthinkable — unleashing a fusillade of shots in the heart of the morning rush on a street loaded with pedestrians.

An NYPD cop on foot patrol — part of the Critical Response Vehicle unit — killed the gunman with one shot.

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